The present invention relates to footwear soles and more particularly to adjustable footwear sole constructions.
The design and manufacture of footwear is complicated by the fact that different people have different footwear needs. For example, some individuals prefer a firmer, more unyielding sole, while others prefer a softer, more cushioning sole. With some people this is simply an aesthetic desire, but for others it can result from physical factors, such as those associated with foot shape, skeletal alignment and other anatomical issues. Anatomical issues cause some individuals to suffer from a tendency to pronate (roll their feet inward when striding) and others to have the opposite tendency to supinate (roll their feet outward when striding). One method for addressing these issues is to stiffen the sole in select regions to provide increased resistance against the undesired motion. For example, pronation can be addressed by providing a dual-density midsole with a higher density region along the medial side of the sole. Similarly, supination can be addressed by providing a dual-density midsole with a higher density region along the lateral side of the sole
In an effort to address the needs of different consumers, a variety of footwear products have been developed with a customizable sole construction. For example, in one conventional product, the sole defines a void adapted to receive one of a variety of different cushioning inserts. With this product, the wearer is provided with different cushioning inserts that meet different cushioning/support needs. The wearer customizes the sole by inserting the appropriate cushioning insert into the void. The insert may be replaced with alternative inserts in the future as desired to alter the characteristics of the sole. Though providing some degree of customization, this solution requires the manufacture and supply of a plurality of inserts. This can increase cost of manufacture and assembly. Further, the consumer is required to save and store the various inserts to permit future adjustment. Additionally, the number of adjustment settings is a function of the number of inserts supplied with the shoe, which has led to relatively limited adjustability in sole constructions of this type.